Ear defender



March 9, 1948. WATSON HA 2,437,490

EAR DEFENDER Filed June 26', 1942 W0 mm? M, n f LNE P nWkaL o 6 55d MAM aws J A MAJTTAWM mmmmfl a N m ww R 9 d b m Patented Mar. 9, 1948 EAR DEFENDER Norman A. Watson, Paul S. Veneklasen, Robert W. Leonard, and Robert S. Gales, Los Angeles, Calif., assignors to the United States of America Application June 26, 1942, Serial No. 448,586

This invention relates to ear defenders or ear protectors and it is a general object of the invention to provide practical and highly eiiective ear defenders which are comfortable and convenient to use.

Another and important object of this invention is to provide ear defenders of the character referred to that may embody novel means for automatically equalizing the air pressure in he auditory canal, between the ear defender and the ear drum, and the pressure at the exterior of the ear defender to prevent injury to the ear drum in situations where the user is subjected to sudden an'd/or substantial changes in air pressure.

Another object of this invention is to provide ear defenders capable of providing the maximum effective sound insulation consistent with the automatic pressure equalization. Experiments indicate that the absolute maximum of sound insulation obtainable by the use of ear defenders is limited by the shear compliance of the skin lining the ear canal and by the bone conduction of the airborne sound impinging on the face and fore-- head. This absolute maximum is achieved only with completely blocked ear canals. The ear protectors of the present invention do not reach this utmost limit of sound insulation. However, they do provide a very substantial insulation and simultaneously provide for the automatic equalization of the air pressures at the opposite sides of the ear defenders.

Another object of this invention is to provide ear protectors that provide the greatest possible degree of sound insulation consistent with the positive retention of the protectors in the auditory canal and the automatic pressure equalization.

Another object of this invention is to provide ear defenders that are durable and sanitary. The ear defenders of the present invention are formed of a. material that is resistant to and unaffected by ear wax, water, soap, alcohol, etc..

Another object of this invention is to provide ear defenders of the character referred to that embody effective sealing means and which readily conform to and seal with the walls of the auditory passage of the average person without pain, irritation or discomfort and provide efiective sound insulation while operating to prevent the entrance of foreign matter into the ears. The means for automatically equalizing the air pressure at the opposite sides of the ear defenders assures the almost instantaneous equalization of the air pressure and yet prevents the entrance of foreign matter into the ears.

1 Claim. ((11. 128'152) The various objects and features of our invention will be fully understood from the following detailed description of typical preferred forms and applications of our invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 i a longitudinal detailed sectional view of a form of ear defender of the present invention embodying an automatic pressure equalizing means. Fig. 2 is an outer end view of the defender and Fig. 3 is a view similar to Fig. 1 illustrating another form of the device.

The embodiment of our invention illustrated in Figs. 1 and 2 of the drawings may be said to comprise, generally, a body I6 designed for insertion in the auditory canal, means H on the body IQ for sealing with the lining of the canal and means ii in the bod it operable to allow for the automatic equalization of the air pressures in said canal and at the exterior of the device while operating as an effective sound insulating element.

The body iii is an elongate plug or stopper proportioned to be readily entered in the canal which has an entrance in the floor of the concha, which canal we shall herein term the auditory canal. In the preferred construction the body it? is hollow or chambered. In the case illustrated in Figs. 1 and 2 of the drawings, the body has a socket or open cavity [3 in its outer end and a similar but somewhat smaller open cavity l i in its entering or inner end, the two cavities being separated by a transverse septum or partition I5. outer portion of the body iii is flared outwardly or is tapered and is substantially round in transverse cross section, it having been determined that this particular shape best adapts the outer portion of the body to fit and seal in the outer portion of the auditory canal. The inner portion of the body ill, which extends inwardly from the transverse plane of the partition 3 5, is reduced in diameter and may be substantially cylindrical. The walls or surfaces of the cavities i3 and I i may correspond in contour to the external shape of the outer and inner portions. respectively, of the body I53 so that the wall of the body it is generally uniform in thickness. However. as clearly illustrated in Fig. l of the drawings, the wall of the outer portion of the body it may be outwardly diminishing in thickness.

The body it is preferabl an integral or one piece element and in accordance with the invention is formed of a yielding resilient material. The body iii may be formed of rubber, synthetic rubber, or the like. In practice we prefer to form the body 10 of the material described and claimed The major 7 in the co-pending application of Paul S. Veneklasen and Norman A. Watson, Serial No. 448,587, filed June 26, 1942, which material is resistant to the action of ear wax, water, soap, and the like, has no objectionable odor and is non-irritating.

The sealing means I I serves to conform to and closely seal with the walls of the auditory canal to provide effective acoustical seals without irritation or discomfort to the user. The sealing means I I includes one or more sealing fins or flanges on the body If). In the structure illustrated there are two spaced sealing flanges I6 and I'I- on the reduced inner portion of the body Iil. The innermost flange I5 is at the inner extremity of the body, while the flange I1 is spaced slightly inward of the transverse plane occupied by the partition I5. and I! are annular and are preferably integral parts of the body Ill. The flanges are shaped to enter the auditory canal with a minimum of resistance and to effectively conform to and seal with the wall of the canal through their inherent resiliency. The flanges I6 and I! are tapered or outwardly diminishing in transverse cross section to have rather thin margins for contacting the wall of the auditory canal. The forward or leading face of the inner flange IB slopes outwardly and rearwardly, while the rear face of this flange is substantially normal to the longitudinal axis of the body I0. Both the forward and rearward faces of the flange I'I slope outwardly and rearwardly but at slightly different angles to give the desired diminishing cross sectional configuration.

The sealing means II further includes a flap or lip I8 on the outer end of the body II]. The lip I8 is preferably a continuous integral part of the body I9 and is designed to engage and seal with the floor of the concha to assist in the sealing action and to position the device in the ear passage to the best advantage. The lip I8 is ovalate in face or end view and because the entrance of the auditory meatus occurs in the upper forward portion of the concha floor the lip I8 is in eccentric or pendent relation to the body Ii] so that it mayflatly bear on the concha floor when the body I is in the meatus. The side or face of the lip I8 which cooperates with the floor of the concha may be pitched outwardly and toward the outer end of the device, while the external face of the lip I8 may be in the same plane as the end of the body ID. It will be seen that the body It) with its sealing and positioning means II is a readily molded one piece part.

The automatic pressure equalizing means I2 is an important feature of the invention. This means I2 operates to permit or provide for an automatic equalization of the air pressure in that portion of the auditory canal between the ear defender and the ear drum and the pressure at the exterior of the ear defender, to prevent injury to the ear drum, etc. in situations where the user is subjected to sudden and/or substantial changes in air pressure. While providing for the automatic equalization of air pressure the means I2 maintains an effective and adequate sound insulation. The means I2 is carried by the partition I and comprises a plug or insert I9 of suitable rigid material, such as a non-corrodible metal; or a metal suitably coated, plated or treated to resist corrosion; or a non-ccrrodible plastic. The insert I9 extends through a central opening in the partition I5 and may besecured and sealed in the partition by suitable cement, or the like. Radial flanges 2D occur on the opposite The flanges I 8 ends of the insert I9 and are cooperable with the inner and outer sides of the partition I5 to dependably prevent displacement of the insert.

The insert I9 is hollow, having a central longitudinal cylindrical cavity or opening 2| entering its outer end. The inner end of the insert I9 is initially closed by a continuous or imperforate wall 22. In accordance with the invention a small perforation or opening 23 is formed in this wall 22. In practice the opening 23 may be a drilled opening of approximately 0.015 of an inch in diameter. The size or diameter of the opening 23 is exaggerated in the drawing in order to illustrate the invention. The cavity or opening 2| extends longitudinally through the insert I 9 from the outer end of the insert to the wall 22 where it joins the perforation or opening 23. In accordance with the invention this cavity or opening 2| of the insert I 9 is filled or packed with acoustical insulation material. In practice cotton 24, or the like, is packed in the opening 2| to provide the required acoustical insulation and yet permit a rapid, pre-controlled, automatic equalization of the air pressures at the opposite sides of the partition I5. The acoustical insulating material or cotton 24 is packed in the opening 2| to form a mass which preferably completely occupies the opening. In practice the cotton 24 may be packed in the opening 2| with a pin, needle, or similar instrument. The insulating material or cotton 24 may be packed to provide the desired degree of air permeability and the desired sound insulation characteristics. The wall 22 effectively prevents the material or cotton 24 from becoming displaced inwardly into the auditory canal and there is little or no tendency for the material to be displaced outwardly; the friction between the closely packed cotton and the internal walls of the insert preventing outward dis placement of the cotton.

It. is to be understood that the ear protector or defender just described may be produced in a suitable range of sizes for use by both adults and children and that the ear defenders are usually used in both ears. In inserting an ear defender in the left ear the user should reach over his head with his right hand and grasp the upper edge of the pinna of the left ear. The pinna is pulled upwardly and backwardly to straighten out the auditory canal. The ear defender is then inserted in the straightened out canal to have the flap or lip I8 engage on the floor of the concha. This completes the insertion of the ear defender and upon relieving the upward and rearward pull of the pinna the defender remains in place in the canal until deliberately removed. An ear defender may be installed in the canal of the right ear in a similar manner.

With the ear defender in position its flanges I6 and I! bear outwardly against the wall or lining of the auditory canal to maintain acoustical sealing engagement therewith. The margins of the flanges I6 and I1 being comparatively thin conform to the irregularities in the canal and the inherent resiliency of the flanges assures the effective conformance of the flanges to the canal. The spaced flanges I6 and I! provide spaced areas or zones of sealing engagement and isolate a dead air space which is effective as a sound insulating unit. The yieldable defender body operates as a compliance unit to provide the best obtainable acoustical insulation. The insert I9 packed with the cotton or material 24 and having the small orifice 23 provides for the equalization of the air pressure in the inner and outer sides of the defender without a too serious loss in acoustical insulation. The closely packed material 24 defines a multitude of small air passages or pores and forms an adequate acoustical insulation while permitting the automatic equalization of the air pressure by air flow through the orifice or opening 23.

The embodiment of the invention illustrated in Fig. 3 of the drawings is similar to the structure of Figs. 1 and 2 but differs therefrom in embodying two air pressure equalizing units or inserts to and Si. The body III of this form of the invention is the same as the body I!) described above except that a septum or partition 32 extends across the mouth of the cavity I 3. All other parts of the defender body It may remain the same as in the previously described form of the invention. Furthermore, the sealing means H may be the same as above described comprising two spaced sealing flanges l6 and I! and an eccentric or depending sealing and positioning lip 18* at the outer end of the body.

The air pressure equalizing unit 30 may be identical with the means l2 above described, comprising a tubular or chambered rigid insert l9 packed with cotton or similar material 24 and provided at its inner end with a small opening 23 The outer partition 32 is preferably, through not necessarily, a continuous integral portion of the body Id. In some cases it may be preferred to make the partition 32 a separately formed element to simplify the manufacture, in which case the partition is cemented or otherwise fixed in the outer end of the body. The outer air pressure equalizing unit 3| may be identical with the unit 30 to reduce the cost of manufacture. Th unit 3| is secured and sealed in a central opening in the partition 32 with its reduced air equalizing opening 23 facing inwardly. The two units 30 and 3| being identical corresponding reference numerals are applied to the corresponding parts.

The ear defender of Fig. 3 operates in substantially the same manner as the device of Figs. 1 and 2. The additional septum or partition 32 and unit 3| may increase the acoustical insulation of the device. It is to be observed that in this structure the cavity 13 constitutes a substantially dead air space connected with the atmosphere and with the auditory canal only by the very small perforations or openings 23 which are acoustically sealed with the cotton or packed material 24.

Having described typical preferred forms and applications of our invention, we do not wish to be limited or restricted to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claim:

Having described our invention, we claim:

An ear protector comprising a body of flexible resilient material including a flared outer portion, a reduced inner portion of substantially cylindrical form, spaced external sealing flanges on said inner portion for sealing with the wall of the auditory canal, a transverse internal partition in said body, and automatic pressure equalizing means carried by said partition, comprising a substantially cylindrical rigid insert extending through a central opening in said partition, radial flanges on the ends of said insert to prevent displacement of the insert, one end of said insert being open and the other end closed except for a minute orifice, said orifice having a cross-sectional area many times smaller than the inside cross-sectional area of the insert, and fibrous material packed in the hollow space within said insert to form acoustical insulation at said orifice and adapted to permit air flow through said orifice for the equalization of pressures at the opposite sides of the partition.

NORMAN A. WATSON. PAUL S. VENEKLASEN. ROBERT W. LEONARD.

ROBERT S. GALES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS FOREIGN PATENTS Country Date Netherlands Nov. 15, 1921 Number Number 

